Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative
Over their highly productive seasonal succession, Arctic diatoms occupy shifting habitats and contrasted light climates defined by snow/ice cover dynamics and extreme photoperiod variations. These unique light environment features suggest Arctic diatoms are well adapted to survive prolonged darkness...
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Université Laval
2019
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fttriple:oai:gotriple.eu:http://hdl.handle.net/20.500.11794/37724 2023-05-15T14:35:13+02:00 Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative Seasonal succession and desperhysiology of Arctic diatoms: relationship between habitat, light niche and photoadaptive strategy Croteau, Dany Babin, Marcel Lavaud, Johann Arctique 2019-01-01 https://hdl.handle.net/20.500.11794/37724 fr fre Université Laval http://hdl.handle.net/20.500.11794/37724 other CorpusUL envir geo Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2019 fttriple https://doi.org/20.500.11794/37724 2023-01-22T18:26:03Z Over their highly productive seasonal succession, Arctic diatoms occupy shifting habitats and contrasted light climates defined by snow/ice cover dynamics and extreme photoperiod variations. These unique light environment features suggest Arctic diatoms are well adapted to survive prolonged darkness periods, exploit minimal light in snow-covered sea-ice and overcome spontaneous excessive, and potentially harmful, light exposures. Diatoms mitigate photooxidative damages by dissipating oversaturating light energy as heat via the non-photochemical quenching (NPQ), mainly regulated by the xanthophyll cycle (XC). How heterogeneous light niches influence Arctic diatoms photoadaptative traits remains largely unknown and a crucial missing link to apprehend Arctic Ocean’s response to shrinking sea-ice and increasing illumination. To address this question, we selected five Arctic diatoms species harbouring diverse life traits and representative of distinct phases across the seasonal light niche continuum: from snow-covered dimly lit bottom sea-ice to summer stratified waters. To access how Arctic diatoms cope with a heterogeneous light environment, we studied their acclimation to two light intensities and subsequent darkness incubations, and parametrized NPQ-XC induction upon light shifts. Our results highlight the sea-ice cover as a strong selective force shaping Arctic diatoms photoadaptative strategies. Ice-related species exhibited a survivalist photoadaptive strategy with growth saturating at low irradiance and strong photoprotective capabilities sustained even in darkness. Open-water species photophysiology was more dynamic, expressing flexible light utilisation capacities and great photoprotection capacities triggered by high light and darkness. Ice-edge species showed strong adaptation to light fluctuations and dark physiology fine-tuned depending upon light history. We argue that diverging photoadaptative strategies foster Arctic diatom success in their respective seasonal niches and will likely drive uneven ... Thesis Arctic Arctique* Sea ice Unknown Arctic |
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Open Polar |
collection |
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op_collection_id |
fttriple |
language |
French |
topic |
envir geo |
spellingShingle |
envir geo Croteau, Dany Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
topic_facet |
envir geo |
description |
Over their highly productive seasonal succession, Arctic diatoms occupy shifting habitats and contrasted light climates defined by snow/ice cover dynamics and extreme photoperiod variations. These unique light environment features suggest Arctic diatoms are well adapted to survive prolonged darkness periods, exploit minimal light in snow-covered sea-ice and overcome spontaneous excessive, and potentially harmful, light exposures. Diatoms mitigate photooxidative damages by dissipating oversaturating light energy as heat via the non-photochemical quenching (NPQ), mainly regulated by the xanthophyll cycle (XC). How heterogeneous light niches influence Arctic diatoms photoadaptative traits remains largely unknown and a crucial missing link to apprehend Arctic Ocean’s response to shrinking sea-ice and increasing illumination. To address this question, we selected five Arctic diatoms species harbouring diverse life traits and representative of distinct phases across the seasonal light niche continuum: from snow-covered dimly lit bottom sea-ice to summer stratified waters. To access how Arctic diatoms cope with a heterogeneous light environment, we studied their acclimation to two light intensities and subsequent darkness incubations, and parametrized NPQ-XC induction upon light shifts. Our results highlight the sea-ice cover as a strong selective force shaping Arctic diatoms photoadaptative strategies. Ice-related species exhibited a survivalist photoadaptive strategy with growth saturating at low irradiance and strong photoprotective capabilities sustained even in darkness. Open-water species photophysiology was more dynamic, expressing flexible light utilisation capacities and great photoprotection capacities triggered by high light and darkness. Ice-edge species showed strong adaptation to light fluctuations and dark physiology fine-tuned depending upon light history. We argue that diverging photoadaptative strategies foster Arctic diatom success in their respective seasonal niches and will likely drive uneven ... |
author2 |
Babin, Marcel Lavaud, Johann |
format |
Thesis |
author |
Croteau, Dany |
author_facet |
Croteau, Dany |
author_sort |
Croteau, Dany |
title |
Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
title_short |
Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
title_full |
Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
title_fullStr |
Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
title_full_unstemmed |
Succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
title_sort |
succession saisonnière et écophysiologie des diatomées arctiques : relation entre l'habitat, la niche lumineuse et la stratégie photoadaptative |
publisher |
Université Laval |
publishDate |
2019 |
url |
https://hdl.handle.net/20.500.11794/37724 |
op_coverage |
Arctique |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctique* Sea ice |
genre_facet |
Arctic Arctique* Sea ice |
op_source |
CorpusUL |
op_relation |
http://hdl.handle.net/20.500.11794/37724 |
op_rights |
other |
op_doi |
https://doi.org/20.500.11794/37724 |
_version_ |
1766308087270998016 |